1. Field of the Invention
The present invention relates to a communication terminal apparatus and a control method thereof, and more particularly, to the communication terminal apparatus having a selection operation unit and the control method thereof.
2. Description of the Related Art
Communication terminal apparatuses such as portable telephones that particularly require portability are commonly used these days. In such communication terminal apparatuses, a single input key has a single function assigned thereto. That is, separate keys such as dial key, communication start key, communication end key, and redial key are assigned independently.
There are some communication terminal apparatuses in which a plurality of functions are assigned to a single input key. However, these functions are not selected by a user but automatically selected according to the state of the communication terminal apparatus. For example, a single input key is used for different operations according to operation state or operation mode of the communication terminal apparatus such as busy or waiting state.
However, if a single function is fixedly assigned to a single input key as described above, the number of input keys inevitably increases number of with increasing functions of communication terminal apparatus. In communication terminal apparatus using a single input key for different functions according to the operation state or the operation mode thereof, the number of input keys is not effectively reduced because functions to be assigned are limited. For example, only a set of functions used only during transmission or a set of functions used only during waiting state can be used for such duplicate assignment.
Further, in a portable communication terminal apparatus such as portable telephone that must have a small size, an increase in the number of input keys results in an increase in the size of the apparatus, and thus there occurs a problem of degraded portability.
Further, the increase in the input keys makes its more number of difficult to select an input key to be operated, which gives an impression that the equipment cannot be operated easily. In addition, there occurs the problem that the user often presses incorrect keys.